After 76 years of operating as a community airport, Braden Airpark is about to go up for sale.

The 72-acre small-plane airfield in Forks Township is taking another step toward closing this week, after no private companies bid to run it.

Technically, fixed-base operators have until Wednesday to make an offer, but no one showed up for the pre-bid conference or airfield tour and the Lehigh-Northampton Airport Authority already has scheduled a Thursday ad seeking someone to buy the single-runway field along Sullivan Trail.

That ad will almost certainly garner bids, but the highest are expected to come from companies interested in closing the airport to redevelop the land.

It's the latest in what appears to be a slow spiral toward closing the airfield where thousands of people have learned to fly or based their planes since it opened in 1938.

"I'm still holding out hope, but it's discomforting that no one is interested in running that airport," said Michael Rosenfeld, president of the Lehigh Valley General Aviation Association. "If Braden closes, it's a disaster for the community."

Authority officials say they can no longer spend money to keep open an airport that is now base to just 30 small-plane operators.

"To be honest, we didn't expect interest from [fixed-base operators]," authority Executive Director Charles Everett Jr. said. "There's no real money to be made at Braden."

Everett said the authority wants to make a decision on the airport by October because the property needs $500,000 worth of capital improvements and the board is determining whether it should cut its losses before investing more.

Taking bids on the land isn't necessarily a death knell for the airport, but it could present authority members with a difficult dilemma because they're likely to get two very different kinds of bids. A group of pilots months ago bid $1.8 million for the airport. That bid was rejected because Everett said it was well below the asking price of at least $3 million — the amount needed to pay off the airport's debt.

Pilots may resubmit that bid or one similar, said Ed Lozano, a leader in the pilots group.

However, the airport is also likely to get bids — perhaps in excess of the $3 million it wants — from developers who want to close Braden and redevelop it for retail, office or residential use. Any such bid likely would be contingent on the buyer being able to change the current zoning designation of recreation, education and municipal.

"With the new Route 33 exit coming, it's a great location," said Martin Till, a regional president for developer J.G. Petrucci Co., which has considered buying it. "But without a zoning change, where's the value? No one is going to want that without a zoning change."

Complicating matters is that if the land stops being used as an airport, the authority will have to repay $1.4 million to $2.8 million in state grants that were issued for work at the airport.

So, that could leave the board with a challenging decision: accept a lower bid from the pilots that keeps it an airport and avoids grant repayments, but leaves the authority with debt; or accept a higher bid from a developer that closes the airport and erases its debt, but leaves the authority negotiating with the state over how much grant money it must return.

Both types of offers have pitfalls. The pilots will need a governmental partner to make it work. Otherwise the airport would lose its nonprofit status and the state grants would probably still have to be repaid. Forks Township has already said it's not interested in taking on that risk, and Northampton County officials haven't decided. Without the county, the pilots can't bid, Lozano acknowledged.

"We are currently in talks with the pilots, concerned citizens and the Lehigh-Northampton Airport Authority and exploring the opportunities on how we can work together to find a mutually successful outcome for Braden Airpark," Northampton County Executive John Brown said in a written statement.

On the other side, a developer would have to wade through a zoning change process that could take months or even years. There'd be no guarantees that approval would come, and even if it did, the airport would have to wait for its money.

"Clearly, we're going to have some decisions to make," Everett said. "But we knew that when this all started. The bottom line is we can't keep losing money on this airport. We have to make a decision."

Under its preset schedule, the authority will close the window for accepting fixed-base operator bids Wednesday, and put the airport land up for sale Thursday. Purchase offers must be in by Aug. 7, and the authority board is scheduled to decide which, if any, to accept.

"I'm less optimistic than I was before," Lozano said. "But I'm hoping cooler heads will prevail. I don't think anyone really wants to see that airport close. There has to be an answer."

If no one bids, Everett said, the authority board could make a decision in late October over whether to close and mothball the airport to avoid adding future costs.